The Mouse Imaging Core of the New York University Cancer Institute (NYUCI) provides services to members utilizing two micro-imaging methods in the living mouse: 1) magnetic resonance micro-imaging (micro-MRI); and 2) ultrasound biomicroscopy (UBM). The focus of this imaging core on mice has been motivated by the increasing use of genetically engineered mice as model systems for studying cancer. Magnetic resonance and ultrasound imaging are indispensable tools used in the clinical diagnosis and staging of human cancer. To realize the full potential of mouse models of cancer, it is imperative to develop n vivo microscopic imaging approaches, allowing analysis, of disease progression and response to therapeutic agents in mice. The Mouse Imaging Core includes a 30-55 MHz UBM scanner and a 7 Tesla micro-MRI system, both situated in the Skirball SPF Mouse Facility, and available for noninvasive microimaging, functional analysis of blood flow and perfusion, as well as UBM-guided manipulation in mice from early embryonic through adult stages of development. The development of instrumentation and imaging approaches to manipulate developmental processes, to detect tumors and to analyze angiogenesis, tumor morphology, progression, regression and metastases has the potential to revolutionize cancer research. In combination with transgenic and gene targeting approaches in the mouse, in vivo microscopic imaging methods provide powerful and efficient new tools for studying the molecular and genetic mechanisms underlying oncogenesis.